/Engine/Source/Runtime/Core/Public/Serialization/CompactBinaryPackage.h
The resolver may return a null buffer to skip resolving an attachment for the hash.
typedef [TFunctionRef](API\Runtime\Core\GenericPlatform\TFunctionRef)< [FSharedBuffer](API\Runtime\Core\Memory\FSharedBuffer)(const [FIoHash](API\Runtime\Core\IO\FIoHash) &Hash)> FAttachmentResolver